Meat’s Effect on the Environment

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Environmental Impact is Highest for Animal Foods

Food choices are personal, but they also have a global reach. What foods we eat (and how they’re produced) can have long-reaching effects on the environment.

Farming Can Lead to Environmental Damage

The costs of eating meat are linked mainly to agricultural practices and factory farming. Though modern and technologically advanced, practices stemming from the agricultural revolution are not sustainable.

What are the connections?

  • Energy: Animals are inefficient calorie converters, taking in up to 40 times more energy from feed than humans yield from eating it.
  • Food supplies: 40% of the world’s grain is fed to livestock instead of to humans (Leitzmann, 2003).
  • Greenhouse gases: Eating one kilogram of beef is equivalent to a three-hour car ride while the lights are left on at home; equivalent to 36.4 kg carbon dioxide (Fanelli, 2007). Food production is responsible for 12% of greenhouse gas emissions (Pazderka et al. n.d.).
  • Habitat destruction: Food production results in 73% of habitat alteration (Pazderka et al. n.d.)

Vegetarianism Diets are More Sustainable

Studies have compared the environmental costs of vegetarian, vegan and omnivorous (meat-eating) diets. Over the past 50 years, world meat consumption has gone up 50%. In 2004, the grain harvest could feed six billion people. But after allocations are made for animals that number is closer to 2.6 billion people (Meat Now, 2004).

  • Meat-eaters eating the same number of calories as vegetarians are responsible for higher land-use. But overall, neither the lacto-ovo vegetarian diets nor omnivorous diets are sustainable.
  • At the same caloric and nutrient levels, vegan diets have the least effect on the environment, followed by vegetarian and omnivorous diets. When organic was compared to conventional systems on each diet, the organic diet wins whether vegan, vegetarian or omnivorous.

Other Environmental Concerns from Agriculture

  • Land use.
  • Water use. To produce 1 calorie of meat it takes 100 times the amount of water that it takes to produce 1 calorie of grain.
  • Transportation. Moving the food to the animals, then moving the animals to slaughter and transporting the meat to a store magnifies harmful emissions
  • Energy and Fossil Fuels. Animals must eat 6 kilograms of plant protein to make 1 kilogram of animal protein. It takes 40 calories of energy to produce one calorie of beef, making it the worst offender. Following close behind are milk (14:1), and eggs (39:1). The average energy-in to energy-out ratio for animal protein is 25:1.

Eco-Friendly Solutions

Experts agree that a decrease or elimination of environmental harm and a sustainable food system are good goals. To work toward these goals, there are “critical points”, or minor dietary changes that have big environmental impacts.

For example:

  • Meat-eaters should reduce their consumption of beef, as it has the worst environmental impact of any food.
  • Cheese, fish and milk are also inefficient at converting energy from fossil fuels into food energy.

Other Dietary Changes can Include:

  • Eating legumes more often, or using them to augment meat dishes. Legumes (beans) are the most energy efficient food to produce.
  • Reduce or eliminate consumption of meat, fowl and fish.
  • Reduce or eliminate consumption of dairy products and eggs.
  • Make Mondays (or another day) meatless, or vegan
  • Buy only free-range animal products, produced in a sustainable manner. Buying pasture-raised beef can lower its energy consumed to energy produced ratio by half.
  • Support local food initiatives, such as urban agriculture, farmers markets and food sharing (community shared agriculture, or CSA)


  • Baroni, L., Cenci, L., Tettama nti, M. and Berati, M. Evaluating the environmental impact of various dietary patterns combined with different food production systems. European Journal of Clinical Nutrition, epub ahead of print, pp 1-8.
  • Fanelli, D. Meat is murder on the environment. New Scientist, 195(2613).
  • Leitzmann, C. Nutrition ecology: the contribution of vegetarian diets. American Journal of Clinical Nutrition, 78(suppl.):657S-659S.
  • Meat now, it’s not personal. World Watch, 17(4):12-19.
  • Pazderka, C., Rowan, A., and Tamm E.E. David Suzuki Foundation. The science of the challenge.
  • Pimentel, D., & Pimental, M. Sustainability of meat-based and plant-based diets and the environment. American Journal of Clinical Nutrition, 78(suppl):660S-663S.